[PSUBS-MAILIST] Light Experiments

[Rick Patton via Personal_Submersibles]

Alan,

Do these pictures have the silicone oil in them? Do you have any side and
back shots of the housing and other data regarding the housing like wall
thickness and what fitting did you use to get the power out of the back and
such?

Rick

On Sat, Apr 15, 2017 at 6:33 PM, Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> I put a temperature probe inside the housing of my 80W LED light.
> The probe was up against the acrylic lens, as I was concerned about
> what temperature the lens was seeing on the inside. The lens is 10mm
> away from the LED.
> The LED manufacturer told me that on normal LEDs the temperature
> out the front of the LED can be 338F (170C) but my flip chips should
> run cooler.
> Briefly; when run at 30W in water they stabilised at 257F after 5 minutes.
> At 45W they stabilised at 280F after 5 minutes. I stopped upping the amps
> at this stage.
> Next experiment, I filled the housing with silicone oil.
> At 45W it hit 116F in 4 minutes & temperature stabilised.
> At 76W it hit 139F in 6 minutes & stabilised.
> So oil has massive advantages in lessening temperature on the lens,
> maybe because it is a buffer from the radiant heat & also transfers the
> heat
> out through the housing quicker.
> Greg your thoughts would be appreciated on this; I am thinking that
> without the
> oil the acrylic lens would see temperatures at which it is formed
> especially
> if I went up to 80W. Although the outside of the lens was cold there would
> be a
> temperature transition across the thickness of the lens & it would be
> considerably
> weakened. I am building to 500ft, so it would potentially see 250 psi in
> operation.
>    At this stage I haven't made up my mind whether to go with a
> borosilicate lens
> or oil fill with an acrylic lens. I had a large bubble & it would be hard
> to eliminate
> all bubbles in the oil filling process.
> Will try & attach photos.
> Alan
>
>
>
>
>
>
>
> Sent from my iPad
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